Asian equity markets opened the week under pressure as investors reacted to stalled diplomatic talks between the United States and Iran and to U.S. plans to move toward a blockade of Iranian ports and the Strait of Hormuz. Regional benchmarks moved in tandem with softer Wall Street futures, where S&P 500 futures fell as much as 1% during Asian trading.
Market anxiety intensified after Brent crude rallied 8% over the weekend and returned above the $100 a barrel threshold. The prospect of a U.S. blockade in Hormuz - a chokepoint through which roughly 20% of the world s oil supplies transit - raised the risk of continued interruptions to oil and gas deliveries to Asia and fed into equity weakness.
Major indexes under pressure
South Korea s KOSPI and Japan s Nikkei 225 recorded the steepest declines in the region, each dropping more than 1%. Japan s TOPIX eased by 0.3%. Elsewhere, Australia s ASX 200 slipped 0.5% while Singapore s Straits Times was down 0.3%.
Chinese markets showed relative resilience: the Shanghai Shenzhen CSI 300 and the Shanghai Composite traded in a flat-to-mildly lower range. By contrast, Hong Kong s Hang Seng fell 1.2%, hit notably by losses in technology shares.
Diplomatic impasse and its trade implications
Marathon negotiations that took place in Pakistan over the weekend between the U.S. and Iran did not produce a meaningful de-escalation of hostilities, according to the reporting in market updates. Washington has announced preparations to blockade Iranian ports and the Strait of Hormuz. While a fragile ceasefire appeared to be holding, with no reports of strikes in the Middle East as of Monday morning, the announcement of the blockade option has amplified concerns about broader trade and energy market disruptions.
The strategic importance of Hormuz for energy flows underpins market sensitivity: about 20% of global oil shipments transit the strait, and economies across Asia are particularly dependent on supplies routed through it. That dependency is one channel through which geopolitical developments in the region translate into market volatility.
Commenting on the market backdrop, OCBC analysts said: "We enter week seven of the US–Iran war with ceasefire now looking fragile… With Brent breaking back above USD100/bbl on renewed escalation risk, equities are the obvious weak link: they have rebounded the most, while bonds have retraced the least."
Recent market moves and positioning
Asian equities had posted solid gains the prior week amid expectations that diplomacy might reduce the chance of further escalation. That prior advance now appears vulnerable to reversal if the conflict shows few signs of abating. Short-term market sentiment has been driven by the interplay of higher oil prices and risk-off dynamics in equities relative to fixed income.
Corporate note: TSMC
In Taiwan, shares of TSMC (TW:2330) edged lower in early trade despite the chipmaker reporting stronger-than-expected revenue for the March quarter. TSMC s revenue rose 35% to T$1.13 trillion, above expectations of T$1.12 trillion, reflecting elevated demand from the artificial intelligence sector. The company, viewed as a gauge of chip and AI demand, is scheduled to release full first-quarter earnings later in the week.
Outlook
For traders and logistics-dependent sectors, the current environment highlights the dual sensitivity of markets to commodity price swings and to potential disruptions in maritime routes. Energy, shipping, and trade-exposed industries remain among the most directly affected if supply interruptions around Hormuz materialize. Equities that had recovered most visibly in recent weeks face the clearest downside risk under renewed escalation.